Both men provided a cheek swab for a DNA Y chromosome test, conducted by Rapid Screenings in Tower Grove. (The results are viewable in a .pdf file below.)

"The Y chromosome test is looking for the paternal line," explains Rapid Screenings' Christi Zalmanoff. "Every male has a Y chromosome. This test basically indicates they have the exact same paternal line. It's pretty cool. Usually the people who do these tests come up empty, especially based on this kind of circumstance."

Zalmanoff notes that there is a slim probability that the pair are actually cousins. The McKellars, though, will never know because their father passed away almost ten years ago and they're not sure if he had any brothers.

"Unfortunately we're not arguing over a $50 million estate," jokes Terrence, a chiropractor from St. Charles. "I wish we were."

Keith McKellar, who lives in Toronto, says he lost contact with his father at the age of ten. Aside from Terrence, he has one younger sibling from his mother's side of the family.

"Frankly, I'm still trying to get my head wrapped around it. It's not everyday that somebody approaches you when you're out of the country and says 'There's a possibility that we're related,'" he says. "[Terrence] is a wonderful man, from what I know of him thus far. I'm really excited at the prospect of getting to know his family and introducing him to mine."

To celebrate their discovery, the newly christened brothers are planning another scuba diving trip in Cozumel this summer.

"At the very least we'll each have ended up with a good friend out of this," Terrence says. "And the mother of all dive stories. Us divers we like to make up stories about all the fish we saw and the sharks we wrestled but this has to be the wildest dive story I've ever heard."McKellar DNA Test Results